1. Field of the Invention
The present invention relates to an electronic beam apparatus and a method for manufacturing a semiconductor device using the electron beam apparatus, and more specifically, to the configuration of a vacuum container and column for an electronic beam apparatus.
2. Description of the Related Art
An apparatus using an electron beam can achieve a higher resolution than an apparatus using light, owing to the small wavelength of an electron beam. Thus, the electron beam is used for a transmission electron microscope, a scanning electron microscope, an electron beam drawing apparatus, and the like. The electron beam is composed of charged particles and is thus controlled by electromagnetic fields. However, a grounding environment may disturb the electromagnetic fields to affect the electron beam. This may make it difficult to control the electron beam. That is, the precision of control of the electron beam may be degraded. To avoid this, a vacuum chamber and a column are made of a magnetic substance having a lower magnetic resistance than the atmosphere, for example, iron; the vacuum chamber stores a sample and the column stores an objective and a condensing lens (Japanese Patent No. 2,993,504). This configuration attracts the magnetic disturbance into the chamber and column. Then, magnetic flux from a magnetic disturbance pass through the chamber and column and are thus prevented from affecting the electron beam.
Magnetic Problem
As described above, the chamber and column are made of the magnetic substance. Thus, when the magnetic disturbance reaches the chamber, a magnetic flux resulting from the magnetic disturbance flows through the magnetic substance constituting the chamber and then toward the column. The column is electromagnetically joined to the objective and condensing lens. Thus, the magnetic flux from the column passes through magnetic poles of the objective and condensing lens. The magnetic flux then seeps from gaps in the lenses. The magnetic flux may degrade the control of the electron beam EB.
Electric Noise Problem
The chamber connects to a pump for vacuum pumping, an measuring instrument for the degree of vacuum, a stage controller, pipe and solenoid valve which sets the pressure in the chamber equal to atmospheric pressure. Further, a solenoid valve for valve control is attached to vacuum pipe. These electric apparatuses make electric noise. The electric noise may vary the reference potentials of power supplies that control the chamber, column, and beam. This degrades the ability to control the electron beam.